Communications systems in general and voice paging systems in particular have attained widespread use for transmitting voice information from a central controller to a selected voice paging receiver. This use has been coupled to the rapid evolution of microcomputers which have allowed paging receivers in general to respond to control signals known as selective call paging signals that identify the type of information transmitted. This information has been transmitted using a number of well known paging coding and message formats, such as POCSAG or Golay Sequential coding (GSC) formats. As a result, the services offered to a paging receiver user have evolved from simple alert plus voice signalling to more complex voice signalling systems. Such systems are relied upon more and more to reach particular individuals wearing such paging receivers to deliver critical and important messages.
Unfortunately, it cannot always be guaranteed that such messages for a particular pager will in fact be received when initially sent. In the past, a voice message was sent without any provision for knowing whether the paging receiver user received it as intended or not. One way to overcome this problem has been to request the paging receiver user to call back the originator of the voice message on the telephone to so advise him. To overcome the annoyance of the paging receiver user calling back the originator, more complex paging systems and paging receivers have begun to use acknowledgment signals. Basically, in response to the selective call paging signals from the central controller, the paging receiver transmits back an acknowledgment signal ("ack-back") that the information has been received.
The above, of course, provides a substantial step toward assuring confidence in the reliability of the paging system. However, to service the acknowledgment signal from the paging receiver, the central controller must switch from a transmission mode to a receive mode and then wait for the acknowledgment signal. This procedure has wasted valuable transmission time, decreased throughput, and increased the complexity of the system. Therefore, a benefit would be obtained if the acknowledge signal from the voice paging receiver could be transmitted during a period of time when the transmitter central controller is normally inactive, such as during the paging receiver alert time. Additionally, receipt of the acknowledgment signal prior to the transmission of the voice message will eliminate wasted transmission time by preventing the transmission of the voice message to an "out of service" pager (either turned off or out of range).
However, even with the paging receiver configured to provide an acknowledgment response, this acknowledgment response was no guarantee the message received was delivered to the paging user, as can occur when the paging receiver is equipped with a user selectable deferred paging mode. When the deferred paging mode was selected, the paging user was not alerted to the receipt of the message until the deferred paging mode was exited, resulting in the loss of the contents of the message. Therefore the paging user was unable to respond to the message, and the message originator was provided with no information as to why the paging user failed to respond to the message.
Concepts for storing voice messages have been proposed. However, messages stored and retrieved at some later time may no longer be applicable to the current situation. Ideally, if the originator were initially informed of the pager status (e.g., that the pager is in the deferred mode), the originator would be in a better position to decide to either proceed with the originally planned message, to change the contents of the message knowing that initially will not be immediately delivered, or abandon altogether. This flexibility significantly improves the utility of the system.